This invention relates to ladders, and in particular to a one, two or more ladder system for raising and lowering platforms and scaffolds on inclined surfaces such as walls and pitched roofs.
Ladders have been used for a variety of job functions from painting walls, cleaning windows, to bringing supplies, such as roofing materials, up to a roof. However, moving materials such as paint cans and brushes and roofing supplies such as shingles and tar, etc. has generally required the worker to physically climb the ladder while simultaneously lifting the supplies with one hand. Clearly, this traditional approach has limitations as to the amount of supplies that can be brought up at any given time. Additionally, having to both lift supplies and climb can be dangerous to the worker when accidents occur. Still furthermore, traditional ladders have not space for storing supplies thereon so that the worker is free to use both their hands. Furthermore, the ladder must often be moved from place to place constantly for many job projects. For example, when painting sides of a building the painter using a single ladder must physically climb down the ladder, move the ladder, a reclimb up the ladder when painting along the side of the building. Also, constantly climbing ladders, and having to physically raise supplies can be dangerous since workers can fall, and persons on the ground adjacent to the ladders can become hurt if something falls on them.
Additionally, the inventor knows of no device or system which would allow a worker to move supplies up other surfaces such as a pitched roof surface when roof shingling is taking place without requiring the worker(s) have to physically lift and carrying the supplies. Thus, traditional pitched roofs are often dangerous places to work since workers must constantly be physically climbing and lifting supplies, and the workers can fall, and persons on the ground adjacent to the ladders can become hurt if something falls on them.
Patents have been proposed over the years for allowing materials to be elevated up the sides of ladders with cranks and motors. See for example, U.S. Pat. No.: 287,042 to Milliken; U.S. Pat. No. 683,890 to Wolfe; U.S. Pat. No. 2,338,833 to Bailey; U.S. Pat. No. 3,428,145 to Lyon; U.S. Pat. No. 3,476,212 to U.S. Pat. No. Eakins; 3,891,062 to Geneste; U.S. Pat. No. 4,183,423 to Lewis; and U.S. Pat. No. 4,546,853 to Hanson. However, these elevator type devices are limited to being used with single ladders, and do not provide any type of work platform that worker(s) can stand and support supplies thereon. Also, these patents are limited to being used on the exterior sides of the ladders which makes them unstable since the supported weight can twist and shift the ladder""s position. Also, none of these devices show any use on other surfaces such as on pitched roof surfaces.
Other patents have been proposed that use two ladders with a plank between them. See for example, U.S. Pat. No. 5,033,584 to Battle, FIG. 5. However, this patent is limited to the user having to physically raise and lower the scaffolding platform which can become tedious and time consuming. One patent U.S. Pat. No. 4,306,700 to Bell proposes a type of chain assembly to hold a platform. However, the chains can damage the rungs and are not practical for long-term use, and the platform(s) must individually be moved and positioned each time a different level is needed. U.S. Pat. No. 6,076,621 to Horn describes a motorized cart having a moveable platform. However, this device uses small caster type wheels that cannot be easily moved over rough and uneven terrain that exists around buildings and homes, etc. Also, the cart requires a completely level surface in order to effectively operate. Furthermore, the cart does not make use of conventional ladders that most workers have access to.
Similar to the single ladder problems, none of the double ladders allow for the moveable platforms to be on the inside surface of the ladder that is leaning against a wall. Still furthermore, none of the double ladders allow for use on raising and lowering supplies, and people, etc. on other inclined surfaces such as but not limited to pitched roof surfaces, and the like.
A primary objective of the invention is to provide an automatic system for simultaneously raising and lowering scaffolding platforms with two or more ladders.
A secondary objective of the invention is to provide an automatic system for raising and lowering scaffolding platforms that can be placed on uneven terrain.
A third objective of the invention is to provide a moveable platform system that can attach on the inside surfaces of a ladder leaning against a structure to allow for greater stability and safety when being used to raise and lower supplies and people
A fourth objective of the invention is to provide a moveable platform system that can be used on a pitched roof surface to raise and lower supplies and people.
A fifth objective of the invention is to provide a moveable platform for ladders that can be enlarged as needed, so that greater amounts of supplies can be used, and more workspace is available, and potentially more workers can use the platform when needed.
A sixth objective of the invention is to provide a moveable platform that can be used with most conventional ladders on the market today, such as single length ladders, extension ladders, large step ladders, and the like.
Further objects and advantages of this invention will be apparent from the following detailed description of a presently preferred embodiment which is illustrated schematically in the accompanying drawings.